The present invention relates to a brake control system, which generates braking torque by controlling a driving source of a vehicle and a hydraulic brake system.
Japanese Patent Provisional Publication No. 7-223532 discloses a brake control system, which controls a regenerative brake system and a hydraulic brake system according to a demanded braking torque calculated according to a depression degree of a brake pedal.
Further, Japanese Patent Publication No. 56-33254 discloses a brake control system, which controls a hydraulic brake system by feeding back a difference between an actual deceleration and a driver""s demand deceleration.
On the assumption that these two techniques are combined, when a desired deceleration is calculated by adding a feedback compensation quantity obtained from an actual deceleration and a deceleration according to the driver""s demand, when both of a hydraulic brake system and a regenerative brake system are controlled to achieve the desired deceleration and when it is intended to improve a fuel consumption, regenerative braking is executed prior to hydraulic braking.
However, the feedback compensation quantity as to the deceleration has a frequency higher than that of the deceleration according to the driver""s demand. Accordingly, if the regenerative brake system generates a maximum braking torque in reply to the deceleration according to the driver""s demand, the feedback compensation quantity tends to be generated by the hydraulic brake system. Since the hydraulic brake system is lower in responsibility and resolution than the regenerative brake system, there is a possibility that this brake control system performs an insufficient responsibility in generating the feedback compensation quantity and thereby degrading the following performance relative to the deceleration according to the driver""s demand.
It is therefore an object of the present invention to provide a brake control system which improves a controllability including a following performance to a driver""s deceleration demand.
An aspect of the present invention resides in a brake control system for a vehicle equipped with a hydraulic brake device and a driving source for driving the vehicle, the brake control comprises a controller configured to divide a desired braking torque into a low-frequency component and a high-frequency component, to command the driving source to generate the high-frequency component, and to command at least one of the hydraulic brake device and the driving source to generate the low-frequency component.
Another aspect of the present invention resides in a brake control system for a vehicle which comprises a first braking device that generates a braking torque by operating a driving source of the vehicle, a second braking device that generates the braking torque by operating a hydraulic brake system of the vehicle, and a controller connected to the first braking device and a second braking device. The controller is configured to calculate a desired braking torque, to divide the desired braking torque into a low-frequency component and a high-frequency component, to command the first braking device to generate the high-frequency component, to command at least one of the first braking device and the second braking device to generate the low-frequency component.
A further another aspect of the present invention resides in a method of controlling a brake control system for a vehicle equipped with a hydraulic brake device and a driving source for driving the vehicle. The brake control comprises a step for dividing a desired braking torque into a low-frequency component and a high-frequency component, a step for distributing the high-frequency component to the driving source to generate a braking torque corresponding to the high-frequency component, and a step for distributing the low-frequency component to at least one of the hydraulic pressure brake device and the driving source to generating a braking torque corresponding to the low-frequency component.
The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.